Polymer emulsions produced by emulsion polymerization of vinyl monomers such as vinyl acetate and acrylate esters are widely used in industry. For example, a polymer emulsion is used as it is in the fields of coating, adhesive, paper modification, and fiber modification, or a polymer separated from a polymer emulsion is used for plastics and rubbers. In emulsion polymerization, as an emulsifier, anionic surfactants such as linear alkylsulfates, linear alkylbenzenesulfonates, polyoxyethylene alkyl ether sulfates, and polyoxyethylene alkylphenyl ether sulfates and nonionic surfactants such as polyoxyethylene linear alkyl ethers, polyoxyethylene alkylphenyl ethers are used alone or as a mixture of anionic/nonionic surfactants.
The emulsifier in emulsion polymerization has much influence not only on initiation of the polymerization and growth of polymer but also on stability of the polymer emulsion during polymerization (polymerization stability) and mechanical, chemical, freeze, and storage stabilities of the resultant polymer emulsion. Surfactants used for emulsion polymerization are required to exhibit good performance on polymerization stability, to produce a polymer emulsion having good mechanical and chemical stabilities, a small particle diameter, and low viscosity, and to cause no environmental problem, and the like.
JP-A-2001-72703 describes a polyoxyethylene alkyl ether sulfate as a surfactant for emulsion polymerization having a small influence on environment.
JP-A-56-72092 (JP-B1-41199) describes a polyoxyalkylene alkyl ether sulfate containing a propyleneoxy group and an ethyleneoxy group as a surfactant for emulsion polymerization.